System for installing a cable in a tower of a wind turbine and method therefor

ABSTRACT

A system for installing an electric cable in a tower of a wind turbine is provided. This system comprises at least one cable drum designed for carrying and controlled releasing of at least one electric cable for a wind turbine. Further, the system contains a drum support for rotatably supporting said at least one cable drum, wherein the drum support is configured to be mounted within an interior of a segment of the tower.

BACKGROUND OF THE INVENTION

The subject matter described herein relates generally to methods andsystems for wind turbines, and more particularly, to methods and systemsconcerning cables in a tower of a wind turbine.

At least some known wind turbines include a tower and a nacelle mountedon the tower. A rotor is rotatably mounted to the nacelle and is coupledto a generator by a shaft. A plurality of blades extend from the rotor.The blades are oriented such that wind passing over the blades turns therotor and rotates the shaft, thereby driving the generator to generateelectricity.

Typically, wind turbines are transported to the site of theirinstallation in a plurality of parts and then assembled on site. Thetransport may occur via transport vehicles or vessels over land (e.g.road and rail) and by sea. The wind turbines may then be erected attheir destination in onshore or offshore locations using the transportvehicle or vessel or by employing further heavy machinery, which isdesigned to lift large and heavy objects.

The tower of the wind turbine usually is assembled from various segmentsat the designated site after a foundation is formed. The single parts ofthe tower are brought to the site separately or preassembled. Further,the tower provides a support for cables electrically connecting thenacelle and its components with further electrical components at groundlevel.

Each part of the tower may come with preinstalled cabling comprising aplurality of cable sections, which need to be connected in order toestablish an electrical connection. Typically, this step is performed byspecially trained staff during or after the erection of the windturbine. Said cable connections may be later a potential subject forfailures.

Wind turbine manufacturers and wind farm operators may desire areduction of the failure risk of the electrical cable connections in thewind turbine tower.

It would therefore be desirable to provide systems and methods allowinga more reliable structure of the cabling in a tower of a wind turbine.

BRIEF DESCRIPTION OF THE INVENTION

In one aspect, a system for installing an electric cable in a tower of awind turbine is provided. This system comprises at least one cable drumdesigned for carrying and controlled releasing of at least one electriccable for a wind turbine. Further, the system contains a drum supportfor rotatably supporting said at least one cable drum, wherein the drumsupport is configured to be mounted within an interior of a segment ofthe tower.

In another aspect, a segment for a tower of a wind turbine is provided.Said segment comprises a longitudinal axis, a lateral wall surroundingthe axis and or a plurality of support beams arranged partially parallelto the axis, a platform mounted therein between mainly perpendicular tothe longitudinal axis for receiving wind turbine related personal andequipment and a system for installing an electric cable in the tower ofa wind turbine, said system comprises at least one cable drum designedfor carrying and controlled releasing of at least one electric cable fora wind turbine and a drum support for rotatably supporting said at leastone cable drum, wherein the drum support is mounted within an interiorof the segment.

In yet another aspect, a method for installing an electric cable to atower of a wind turbine is provided, the method comprising the followingsteps: (a) providing a system for installing the electrical cable withinan interior of the at least one tower segment; (b) mounting a drumsupport for rotatably supporting at least one cable drum to the interiorof the at least one tower segment; (c) mounting at least one cable drumcarrying at least one electric cable for a wind turbine to the drumsupport; (d) erecting the tower including lifting the at least one towersegment; (e) unwinding the electric cable essentially parallel to thelongitudinal axis through an opening in or near the platform; (f) fixingthe cable in respect to the segment; (g) optionally repeating steps e)to f).

In an additional other aspect, a cable drum adapted for use in a systemfor installing an electric cable in a tower of a wind turbine isprovided, wherein the system comprises a drum support for rotatablysupporting the cable drum and the drum support is configured to bemounted within an interior of a segment of the tower, the cable drumcomprises at least one electric cable for a wind turbine having a weightof more than 100 kilograms and a length of more than 60 meters, and thecable drum is designed for carrying and controlled releasing of saidcable

Further aspects, advantages and features of the present invention areapparent from the dependent claims, the description and the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure including the best mode thereof, to oneof ordinary skill in the art, is set forth more particularly in theremainder of the specification, including reference to the accompanyingfigures wherein:

FIG. 1 is a perspective view of an exemplary wind turbine.

FIG. 2 is an enlarged sectional view of a portion of the wind turbineshown in FIG. 1.

FIG. 3 is an exploded view of a system for installing an electricalcable.

FIG. 4 is a perspective view of a disassembled cable drum of the systemshown in FIG. 3.

FIG. 5 is a perspective view of an embodiment of a cable drum for asystem for installing a cable.

FIG. 6 is a perspective view into a segment of a tower of a wind turbineaccording to a first embodiment comprising a system for installing anelectrical cable.

FIG. 7 is a sectional view of the segment according to the firstembodiment.

FIG. 8 is a perspective view in a segment of a tower of a wind turbineaccording to a second embodiment comprising a system for installing anelectrical cable.

FIG. 9 is a sectional view of the segment according to the secondembodiment.

FIG. 10 is a perspective view in the segment according to the firstembodiment comprising a saddle for supporting electrical cables.

FIG. 11 is a perspective view in the segment according to the secondembodiment comprising a saddle for supporting electrical cables.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the various embodiments, one ormore examples of which are illustrated in each figure. Each example isprovided by way of explanation and is not meant as a limitation. Forexample, features illustrated or described as part of one embodiment canbe used on or in conjunction with other embodiments to yield yet furtherembodiments. It is intended that the present disclosure includes suchmodifications and variations.

The embodiments described herein include a system for installing anelectric cable in a tower of a wind turbine, a cable drum adapted foruse in said system, a segment for a tower of a wind turbine and a methodfor installing an electric cable to said tower, wherein an electricalconnection comprising a cable for said tower is provided, which hasimproved fail-safe characteristics. More specifically, it is notrequired anymore to assemble the electrical connection by connecting aplurality of various cable segments via a plurality of connectiondevices. This leads to a reduction of components prone to failure andsubsequently to an increased reliability of the electrical connection.Thus, no maintenance work therefor is required and a related downtime ofoperation of the wind turbine is avoided. In addition, due to shortenedinstallation time and effort and less components assembled an overallcost reduction is achieved.

As used herein, the term “wind turbine” is intended to be representativeof any device that generates rotational energy from wind energy, andmore specifically, converts kinetic energy of wind into mechanicalenergy.

As used herein, the term “wind generator” is intended to berepresentative of any wind turbine that generates electrical power fromrotational energy generated from wind energy, and more specifically,converts mechanical energy converted from kinetic energy of wind toelectrical power.

As used herein, the term “tower of a wind turbine” is intended to berepresentative of any support structure of a wind turbine that isadapted to carry a nacelle of a wind turbine.

As used herein, the term “segment” of a tower of a wind turbine isintended to be representative of any structural component which forms atleast one structural part of the tower of the wind turbine. The towermay comprise a plurality or only one of such segments. Said segment canbe a steel wall surrounding a longitudinal axis or a lattice structurewherein lattice beams are arranged to function as a longitudinal latticesegment.

As used herein, the term “interior” of a segment is intended to berepresentative of any space within the structure of the segment whilethe outer limits of such space may be for real or of imaginary natureformed by said structure of the segment. For example, a space within theupper mentioned steel wall or a space surrounded by lattice beamswithout separate walls is considered as interior of a segment.

As used herein, the term “cable drum” is intended to be representativeof any structure designed for carrying a cable in any manner,independently from the way a cable is arranged or attached to thisstructure.

FIG. 1 is a perspective view of an exemplary wind turbine 10. In theexemplary embodiment, wind turbine 10 is a horizontal-axis wind turbine.Alternatively, wind turbine 10 may be a vertical-axis wind turbine. Inthe exemplary embodiment, wind turbine 10 includes a tower 12 thatextends from a support system 14, a nacelle 16 mounted on tower 12, anda rotor 18 that is coupled to nacelle 16. Rotor 18 includes a rotatablehub 20 and at least one rotor blade 22 coupled to and extending outwardfrom hub 20. In the exemplary embodiment, rotor 18 has three rotorblades 22. In an alternative embodiment, rotor 18 includes more or lessthan three rotor blades 22. In the exemplary embodiment, tower 12 isfabricated from tubular steel to define a cavity (not shown in FIG. 1)between support system 14 and nacelle 16. In an alternative embodiment,tower 12 is any suitable type of tower having any suitable height.

Rotor blades 22 are spaced about hub 20 to facilitate rotating rotor 18to enable kinetic energy to be transferred from the wind into usablemechanical energy, and subsequently, electrical energy. Rotor blades 22are mated to hub 20 by coupling a blade root portion 24 to hub 20 at aplurality of load transfer regions 26. Load transfer regions 26 have ahub load transfer region and a blade load transfer region (both notshown in FIG. 1). Loads induced to rotor blades 22 are transferred tohub 20 via load transfer regions 26.

In one embodiment, rotor blades 22 have a length ranging from about 15meters (m) to about 91 m. Alternatively, rotor blades 22 may have anysuitable length that enables wind turbine 10 to function as describedherein. For example, other non-limiting examples of blade lengthsinclude 10 m or less, 20 m, 37 m, or a length that is greater than 91 m.As wind strikes rotor blades 22 from a direction 28, rotor 18 is rotatedabout an axis of rotation 30. As rotor blades 22 are rotated andsubjected to centrifugal forces, rotor blades 22 are also subjected tovarious forces and moments. As such, rotor blades 22 may deflect and/orrotate from a neutral, or non-deflected, position to a deflectedposition.

Moreover, a pitch angle or blade pitch of rotor blades 22, i.e., anangle that determines a perspective of rotor blades 22 with respect todirection 28 of the wind, may be changed by a pitch adjustment system 32to control the load and power generated by wind turbine 10 by adjustingan angular position of at least one rotor blade 22 relative to windvectors. Pitch axes 34 for rotor blades 22 are shown. During operationof wind turbine 10, pitch adjustment system 32 may change a blade pitchof rotor blades 22 such that rotor blades 22 are moved to a featheredposition, such that the perspective of at least one rotor blade 22relative to wind vectors provides a minimal surface area of rotor blade22 to be oriented towards the wind vectors, which facilitates reducing arotational speed of rotor 18 and/or facilitates a stall of rotor 18.

In the exemplary embodiment, a blade pitch of each rotor blade 22 iscontrolled individually by a control system 36. Alternatively, the bladepitch for all rotor blades 22 may be controlled simultaneously bycontrol system 36. Further, in the exemplary embodiment, as direction 28changes, a yaw direction of nacelle 16 may be controlled about a yawaxis 38 to position rotor blades 22 with respect to direction 28.

In the exemplary embodiment, control system 36 is shown as beingcentralized within nacelle 16, however, control system 36 may be adistributed system throughout wind turbine 10, on support system 14,within a wind farm, and/or at a remote control center. Control system 36includes a processor 40 configured to perform the methods and/or stepsdescribed herein. Further, many of the other components described hereininclude a processor. As used herein, the term “processor” is not limitedto integrated circuits referred to in the art as a computer, but broadlyrefers to a controller, a microcontroller, a microcomputer, aprogrammable logic controller (PLC), an application specific integratedcircuit, and other programmable circuits, and these terms are usedinterchangeably herein. It should be understood that a processor and/ora control system can also include memory, input channels, and/or outputchannels.

In the embodiments described herein, memory may include, withoutlimitation, a computer-readable medium, such as a random access memory(RAM), and a computer-readable non-volatile medium, such as flashmemory. Alternatively, a floppy disk, a compact disc-read only memory(CD-ROM), a magneto-optical disk (MOD), and/or a digital versatile disc(DVD) may also be used. Also, in the embodiments described herein, inputchannels include, without limitation, sensors and/or computerperipherals associated with an operator interface, such as a mouse and akeyboard. Further, in the exemplary embodiment, output channels mayinclude, without limitation, a control device, an operator interfacemonitor and/or a display.

Processors described herein process information transmitted from aplurality of electrical and electronic devices that may include, withoutlimitation, sensors, actuators, compressors, control systems, and/ormonitoring devices. Such processors may be physically located in, forexample, a control system, a sensor, a monitoring device, a desktopcomputer, a laptop computer, a programmable logic controller (PLC)cabinet, and/or a distributed control system (DCS) cabinet. RAM andstorage devices store and transfer information and instructions to beexecuted by the processor(s). RAM and storage devices can also be usedto store and provide temporary variables, static (i.e., non-changing)information and instructions, or other intermediate information to theprocessors during execution of instructions by the processor(s).Instructions that are executed may include, without limitation, windturbine control system control commands. The execution of sequences ofinstructions is not limited to any specific combination of hardwarecircuitry and software instructions.

FIG. 2 is an enlarged sectional view of a portion of wind turbine 10. Inthe exemplary embodiment, wind turbine 10 includes nacelle 16 and hub 20that is rotatably coupled to nacelle 16. More specifically, hub 20 isrotatably coupled to an electric generator 42 positioned within nacelle16 by rotor shaft 44 (sometimes referred to as either a main shaft or alow speed shaft), a gearbox 46, a high speed shaft 48, and a coupling50. In the exemplary embodiment, rotor shaft 44 is disposed coaxial torotational axis 92. Rotation of rotor shaft 44 rotatably drives gearbox46 that subsequently drives high speed shaft 48. High speed shaft 48rotatably drives generator 42 with coupling 50 and rotation of highspeed shaft 48 facilitates production of electrical power by generator42. Gearbox 46 and generator 42 are supported by a support 52 and asupport 54. In the exemplary embodiment, gearbox 46 utilizes a dual pathgeometry to drive high speed shaft 48. Alternatively, rotor shaft 44 iscoupled directly to generator 42 with coupling 50.

Nacelle 16 also includes a yaw drive mechanism 56 that may be used torotate nacelle 16 and hub 20 on yaw axis 38 (shown in FIG. 1) to controlthe perspective of rotor blades 22 with respect to direction 28 of thewind. Nacelle 16 also includes at least one meteorological mast 58 thatincludes a wind vane and anemometer (neither shown in FIG. 2). Mast 58provides information to control system 36 that may include winddirection and/or wind speed. In the exemplary embodiment, nacelle 16also includes a main forward support bearing 60 and a main aft supportbearing 62.

Forward support bearing 60 and aft support bearing 62 facilitate radialsupport and alignment of rotor shaft 44. Forward support bearing 60 iscoupled to rotor shaft 44 near hub 20. Aft support bearing 62 ispositioned on rotor shaft 44 near gearbox 46 and/or generator 42.Alternatively, nacelle 16 includes any number of support bearings thatenable wind turbine 10 to function as disclosed herein. Rotor shaft 44,generator 42, gearbox 46, high speed shaft 48, coupling 50, and anyassociated fastening, support, and/or securing device including, but notlimited to, support 52 and/or support 54, and forward support bearing 60and aft support bearing 62, are sometimes referred to as a drive train64.

In the exemplary embodiment, hub 20 includes a pitch assembly 66. Pitchassembly 66 includes one or more pitch drive systems 68 and at least onesensor 70. Each pitch drive system 68 is coupled to a respective rotorblade 22 (shown in FIG. 1) for modulating the blade pitch of associatedrotor blade 22 along pitch axis 34. Only one of three pitch drivesystems 68 is shown in FIG. 2.

In the exemplary embodiment, pitch assembly 66 includes at least onepitch bearing 72 coupled to hub 20 and to respective rotor blade 22(shown in FIG. 1) for rotating respective rotor blade 22 about pitchaxis 34. Pitch drive system 68 includes a pitch drive motor 74, pitchdrive gearbox 76, and pitch drive pinion 78. Pitch drive motor 74 iscoupled to pitch drive gearbox 76 such that pitch drive motor 74 impartsmechanical force to pitch drive gearbox 76. Pitch drive gearbox 76 iscoupled to pitch drive pinion 78 such that pitch drive pinion 78 isrotated by pitch drive gearbox 76. Pitch bearing 72 is coupled to pitchdrive pinion 78 such that the rotation of pitch drive pinion 78 causesrotation of pitch bearing 72. More specifically, in the exemplaryembodiment, pitch drive pinion 78 is coupled to pitch bearing 72 suchthat rotation of pitch drive gearbox 76 rotates pitch bearing 72 androtor blade 22 about pitch axis 34 to change the blade pitch of blade22.

Pitch drive system 68 is coupled to control system 36 for adjusting theblade pitch of rotor blade 22 upon receipt of one or more signals fromcontrol system 36. In the exemplary embodiment, pitch drive motor 74 isany suitable motor driven by electrical power and/or a hydraulic systemthat enables pitch assembly 66 to function as described herein.Alternatively, pitch assembly 66 may include any suitable structure,configuration, arrangement, and/or components such as, but not limitedto, hydraulic cylinders, springs, and/or servo-mechanisms. Moreover,pitch assembly 66 may be driven by any suitable means such as, but notlimited to, hydraulic fluid, and/or mechanical power, such as, but notlimited to, induced spring forces and/or electromagnetic forces. Incertain embodiments, pitch drive motor 74 is driven by energy extractedfrom a rotational inertia of hub 20 and/or a stored energy source (notshown) that supplies energy to components of wind turbine 10.

Pitch assembly 66 also includes one or more overspeed control systems 80for controlling pitch drive system 68 during rotor overspeed. In theexemplary embodiment, pitch assembly 66 includes at least one overspeedcontrol system 80 communicatively coupled to respective pitch drivesystem 68 for controlling pitch drive system 68 independently of controlsystem 36. In one embodiment, pitch assembly 66 includes a plurality ofoverspeed control systems 80 that are each communicatively coupled torespective pitch drive system 68 to operate respective pitch drivesystem 68 independently of control system 36. Overspeed control system80 is also communicatively coupled to sensor 70. In the exemplaryembodiment, overspeed control system 80 is coupled to pitch drive system68 and to sensor 70 with a plurality of cables 82. Alternatively,overspeed control system 80 is communicatively coupled to pitch drivesystem 68 and to sensor 70 using any suitable wired and/or wirelesscommunications device. During normal operation of wind turbine 10,control system 36 controls pitch drive system 68 to adjust a pitch ofrotor blade 22. In one embodiment, when rotor 18 operates at rotoroverspeed, overspeed control system 80 overrides control system 36, suchthat control system 36 no longer controls pitch drive system 68 andoverspeed control system 80 controls pitch drive system 68 to move rotorblade 22 to a feathered position to slow a rotation of rotor 18.

A power generator 84 is coupled to sensor 70, overspeed control system80, and pitch drive system 68 to provide a source of power to pitchassembly 66. In the exemplary embodiment, power generator 84 provides acontinuing source of power to pitch assembly 66 during operation of windturbine 10. In an alternative embodiment, power generator 84 providespower to pitch assembly 66 during an electrical power loss event turbine10. The electrical power loss event may include power grid loss,malfunctioning of the turbine electrical system, and/or failure of thewind turbine control system 36. During the electrical power loss event,power generator 84 operates to provide electrical power to pitchassembly 66 such that pitch assembly 66 can operate during theelectrical power loss event.

In the exemplary embodiment, pitch drive system 68, sensor 70, overspeedcontrol system 80, cables 82, and power generator 84 are each positionedin a cavity 86 defined by an inner surface 88 of hub 20. In a particularembodiment, pitch drive system 68, sensor 70, overspeed control system80, cables 82, and/or power generator 84 are coupled, directly orindirectly, to inner surface 88. In an alternative embodiment, pitchdrive system 68, sensor 70, overspeed control system 80, cables 82, andpower generator 84 are positioned with respect to an outer surface 90 ofhub 20 and may be coupled, directly or indirectly, to outer surface 90.

In the exemplary embodiment, the tower 12 of the wind turbine 10comprises a tower segment 104 having a system 100 for installing anelectric cable 102 into said tower 12. The system 100 comprises a cabledrum 120 adapted for a use in said system 100. This is explained in moredetail with regard to FIG. 3.

The system 100 shown FIG. 3 comprises the cable drum 120 and the drumsupport 114 for rotatably supporting the cable drum 120. The cable drum120 is adapted to be carried by the drum support 114 and is furtherdesigned for carrying and controlled releasing of at least one electriccable 102 for the wind turbine 10. For example, controlled release ofcable 102 from cable drum 120 includes controlling a speed of unwinding.Additionally or alternatively, controlled release of cable 102 may alsoinclude controlling a direction in which the cable 102 is released. Thesystem 100 is further adapted for being mounted within an interior ofthe segment of the wind turbine tower.

According to a non-limiting embodiment, the drum support 114 comprisesreleasable connectors 115 for mounting the drum support 114 to an innersurface 112 of a lateral wall 110 of the segment 104. According to analternative or additional embodiment the releasable connectors 115 areadapted to be attached to a receptacle 130 located on an inner surface112 of the wall 110 of the segment 104.

According to the embodiment in FIG. 3 the drum support 114 of the system100 is formed by an attachment device 116 and an axle 118 whichrotatably carries the cable drum 120. Alternatively, an axle can berotatably held by the attachment device 116 and can rotate together withthe cable drum 120. Hence, the system 100 allows directly or indirectlymounting the cable drum 100 to the segment 104.

According to a further embodiment,—as it is exemplary shown in theexploded views in FIGS. 3 and 4—the system 100 itself can bedisassembled in at least two separate components.

Hence it is possible to easily transport the single components throughan opening 126 in a platform 124 down the tower 12 of the wind turbineto the ground when the installation of cables 102 is complete.

According to the present example the system 100 can be disassembled intoa plurality of sub-components—drum support 114, attachment device 116and cable drum 120. Those components can be brought down through theinterior of the tower 12. Typically, the said sub-components have anappropriate size in order to fit through an opening 126 of the platform124 in the tower segment 104. For example, these sub-components can bewinched down.

According to a further embodiment, the cable drum 120 can bedisassembled into six parts, two half parts of the drum body 121 andfour half parts of the drum boundary 123.

According to an embodiment, said cable 102 has at least a weight of morethan 100 kilograms and a length of more than 60 meters. According to anembodiment the cable has a length of more than 500 m and according toanother embodiment more than 1000 m.

According to the embodiment shown in FIG. 5, a system 200 for installinga cable 102 into a segment 104 of a tower 12 of the wind turbine 10comprises a plurality of cable drums 202. Thus, the system 200 may carrya plurality of different electric cables 102 which are installed forconnecting electrical components of the nacelle 16 to further electriccomponents at the bottom area of the wind turbine tower 12. According toa non-limiting example, such cables may connect a stator and a rotor ofthe electric generator 42 to an inverter system or transformer arrangedin the bottom part of the tower.

According to an embodiment the cables may be of the same type or ofdifferent types. By this measure the installation process is renderedmore efficient since parallel cables 102 can be unwound at the sametime. Alternatively or additionally, the system 100 for installing acable may comprise a plurality of cables 102 which may be unwound inparallel or sequentially. The sequence of unwinding cables 102 isadapted to the type, length and quantity of cables to be installed intothe tower.

According to an embodiment (not shown), each cable drum 202 is supportedindependently by the system 200 such that it may rotate independently ofother cable drums. In case different types of cables are installed, theinstallation process is rendered more efficient.

According to an embodiment, such multiple cable drums 125 comprise aplurality of drum bodies 121 and drum boundaries 125.

FIG. 6 shows a three dimensional view into an interior of the segment104 of the tower 12, wherein FIG. 7 represents a sectional view throughthe tower segment 104 showing a view from above onto a platform 124 ofthe tower segment 104. The following description refers to both, FIGS. 6and 7.

The segment shown in FIGS. 6 and 7 has a tubular wall 110 which can bemade of steel. The wall 110 stretches mostly circular along alongitudinal axis 106 which can be aligned or substantially parallel tothe yaw axis 38. In FIG. 6 the wall 110 is shown schematically only, inorder to allow a focus in the interior 108 of the segment 104 of thetower 12. Alternatively or additionally, the wall of a segment may bemade from any other suitable material in a tubular or non-tubular styleor a segment can be formed from concrete or assembled from a pluralityof concrete rings or ring segments.

Platform 124 is arranged within the interior 108 of the segment 104 toenable installation and maintenance staff to access an upper part of thetower segment 104 and to facilitate the assembly of components. Saidplatform 124 can be arranged perpendicular to the longitudinal axis 106.According to the present example, the platform 124 in the upper part ofthe segment 104 is facing an area of the tower 12 in which a gear rim128 of a yaw bearing system is mounted to a top flange of the towersegment 104 of the tower 12. In this context, the upper part of thetower segment 104 is an area mostly distanced from the foundationsupport system 14 of the erected tower 12. Additionally oralternatively, the platform 124 can be arranged in any part of thesegment 104 of the tower 12.

Within the interior 108 of the tower 12 the system 100 for installing anelectrical cable 102 is detachably mounted to an inner surface 112 ofthe wall 110. According to an alternative embodiment, the system 100 maybe attached to any structure in the interior 108 of the tower segment104. The attachment is done in such, that the weight of the system 100device is be transmitted into the segment 104. A mounting location inthe interior 108 is adapted to be suitably for carrying the mass of thesystem 100 and transmitting related forces into the structure of thetower segment 104.

According to another embodiment, the system 100 is mounted to thesegment 104 such that the entire cable drum 120 is fully arranged withinthe interior of the segment 104. Thus, the system 100 comprising thedrum support 114 and the cable drum 120 can be preassembled in the towersegment 104 before the tower 12 itself is erected. Hence, cables 102 forelectrically connecting the nacelle 16 or components therein to groundequipment are already provided within the tower segment 104 in awound-in form. Therefore, the entire tower 12 may be erected, thenacelle 16 may be placed onto the tower 12 and cabling is not requiredto be brought up towards the nacelle 16.

Another embodiment is presented in FIG. 10 in connection to FIGS. 6 and7. The exemplary segment 104 comprises a receptacle 130 on a radiallyinner surface 112 of the lateral wall 110. During normal operation ofthe wind turbine 10—hence, after erection and commissioning—thereceptacle 130 carries a cable saddle 132 for supporting electricalcables 102 in a transition area between a nacelle 16 and the towersegment 104. Between the basic support 14 of the tower 12 and the cablesaddle 132 said cables 102 are fixed with respect to the wall 110. Dueto the fact that the nacelle 16 is rotating during operation withrespect to the tower 12, cables 102 between nacelle 16 and cable saddle132 become twisted according to nacelle's 16 rotation. For that reason acable section of the electrical cables 102 between the nacelle 16 andthe cable saddle 132 hangs freely and some twisting of the cables 102 isallowed.

The drum support 114 of the system 100 for installing an electricalcable 102 in a tower segment 104 is designed to fit to the receptacle130. Hence, no separate mounting arrangement for fixing the system tothe tower segment 104 needs to be provided. This speeds up thepreassembling process and—due to an increased homogeneity of the segmentstructure—it supports the structural integrity of the tower segment 104.

According to an alternative embodiment (not shown) a segment comprisesanother type of receptacle for mounting or attaching further componentsto the segment. The system for installing an electric cable may bemounted to such other type of receptacle.

According to a further embodiment (not shown), a longitudinal ladder ismounted to the inner surface 112 of the lateral wall 110 of the towersegment 104. Further, the tower segment 104 comprises fixation means forfixing the cable 102 with respect to the tower segment 104, wherein thefixation means are mounted in vicinity of the ladder such thatinstallation personal may to access the fixation means from the ladderfor mounting the cable 102. Thus, the installation personal may easilyfix the cables with respect to the tower without climbing off theladder. This results in a more cost effective and less time-consuminginstallation process.

According to an embodiment of erecting the tower 12 of the wind turbine10, a bottom segment is mounted onto the foundation support system 14and a further segment or further segments are put and fixed on top ofeach other. The most upper tower segment 104 comprises the system 100for installing a cable 102 in tower 12. The system 100 can be mounted tothe inner surface 112 of the wall 110 in near platform 124 such thatpersonal is able to reach it when standing on the platform 124.

For installing a cable 102 in the assembled tower 12, the cable 102 isreleased from the cable drum 120 by unwinding it from the cable drum 120manually. Alternatively or additionally, the system may include anactive drive for unwinding the cable. Subsequently, the cable 102 islowered through an opening 126 or gap in the platform until the lowerend of the cable 102 reaches its intended location. Subsequently, thecable 102 is directly or indirectly fixed by special fixation means tothe tower segment 104.

This step of the method for installing a cable 102 in a tower 12 of windturbine 10 is repeated until all electrical cables 102 are installed inthe tower 12. This method comes with the benefit that one continuouscable 102 without intermediate connection can be easily installed intothe tower 12, wherein connection means for connecting the cable segmentsare not required any longer. A continuous electrical cable 102 is lessprone to failure, which leads to an increased reliability of the wholewind turbine 10.

Furthermore, installation time is shortened drastically: before erectingthe tower 12 from tower segments 104 the system 100 for installing thecable 102 is preassembled into the upper tower segment 104 and equippedwith the very cable 102. Thus, when erecting the tower 12 the system 100for installing the cable 102 is lifted to the top of the tower 12,already mounted in the upper tower segment 104. When the tower 102 iserected, the cable 102 is easily released top-down along the length ofthe entire tower 12 by simply unwinding the cable drum 120 and utilizinggravity. This method requires less components and working steps as ifthe cable 102 was carefully pulled up through the tower or was beingassembled from various cable segments.

According to an additional embodiment, the step of releasing the cable102 from the cable drum 120 does not require electrical energy, e.g. foroperating an electric drive. During the installation process, the cabledrum 120 can be rotated and controlled by installation staff beingpresent on the platform 124 near by the cable drum 120. Thus, it is notrequired to install a supply of electrical energy into the tower 12 inorder to drive an interims installation device like a winch orelectrical drive. Thus, the installation process is rendered lesscomplex and less prone to errors.

According to the embodiment in FIG. 3, 6 and FIG. 7 a locking device 122is provided which acts between the drum support 114 and the cable drum120 for preventing an undesired rotation of the cable drum 120.Additionally, the locking device 122 can be configured in such that itacts as brake for the cable drum 120. By this, the speed of rotation ofthe cable drum 120 can be controlled when the cable 102 is released downfrom the platform 124 towards the bottom. However, according to analternative embodiment, the locking device or brake may be omitted. Thisis beneficial and applicable if the cable drum 120 allows a manual,controlled unwinding and holding.

According to an additional embodiment, the cable 102 is cut from thecable drum 120 when being successfully released and fixed with respectto the tower segment 104. This is particularly applicable, if aplurality of cables 102 of the same type is to be installed in the tower12. In this case, the cable drum 120 comprises one continuous cable 102being sufficiently long. After cutting the cable 102 the cable 102 isfurther unwound from the cable drum 120 and released downwards throughopenings 126 in the platform 124 in the tower segment 104 of the tower12.

Alternatively or additionally, after the unwinding cable 102 from cabledrum 120 is completed, the system 100 is dismounted off the towersegment 104 and disassembled into at least two separate components. Asshown in the non-limiting example according to FIG. 3, the drum support114 may be disassembled in axle 118 and attachment device 116.

According to an additional or alternative embodiment shown in FIG. 5,the cable drum 120 may be disassembled accordingly in smaller componentssuch as half parts of the drum body 121 and half parts of the drumboundaries 123.

According to the present example, the system 100 is disassembled incomponents which have a size for fitting through an opening 126 withinthe platform 124.

According to a further embodiment, the disassembled components of thesystem 100 are lowered down from the tower 12. For that purpose a winchor an adapted rope can be used. No external crane is required todismount the system 100 from the tower 12.

According to an additional embodiment, after dismounting the system 100from the receptacle 130 the cable saddle 132 is mounted to saidreceptacle 130 on the wall 110 of the tower segment 104.

Another embodiment is disclosed in FIGS. 8, 9 and 11, wherein a tower ofa wind turbine is of the lattice tower type. Therefore the tower segment134 is formed by a plurality of lattice beams 136. Typically, thelattice beams 136 are built on site and subsequently assembled to form alattice segment 134. Such lattice segments 134 are then mounted on topon each other to form the tower.

The exemplary lattice segment 134 defines an interior 140 which is thespace defined by the lattice beams 136. Typically, but not limited to,four lattice beams 136 define the interior 140 of the lattice segment134. The lattice segment 134 carries a platform 138 similar to the towersegment 104 mentioned above.

One or a combination of the embodiments mentioned above may be appliedto the embodiment shown in FIGS. 8 and 9. Like components in FIGS. 8 and9 have the same reference numerals as in FIGS. 6 and 7.

Exemplary embodiments of systems and methods for installing a cable in atower of the wind turbine are described above in detail. The systems andmethods are not limited to the specific embodiments described herein,but rather, components of the systems and/or steps of the methods may beutilized independently and separately from other components and/or stepsdescribed herein. For example a system for installing a cable in thetower and the related method thereto are not limited to practice withonly the wind turbine systems as described herein. Rather, the exemplaryembodiment can be implemented and utilized in connection with many othertower applications.

Although specific features of various embodiments of the invention maybe shown in some drawings and not in others, this is for convenienceonly. In accordance with the principles of the invention, any feature ofa drawing may be referenced and/or claimed in combination with anyfeature of any other drawing.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. While various specificembodiments have been disclosed in the foregoing, those skilled in theart will recognize that the spirit and scope of the claims allows forequally effective modifications. Especially, mutually non-exclusivefeatures of the embodiments described above may be combined with eachother. The patentable scope of the invention is defined by the claims,and may include other examples that occur to those skilled in the art.Such other examples are intended to be within the scope of the claims ifthey have structural elements that do not differ from the literallanguage of the claims, or if they include equivalent structuralelements with insubstantial differences from the literal language of theclaims.

What is claimed is:
 1. A system for installing an electric cable in atower of a wind turbine, comprising: at least one cable drum designedfor carrying and controlled releasing of at least one electric cable fora wind turbine; a drum support for rotatably supporting said at leastone cable drum, wherein the drum support is configured to be within aninterior of a segment of the tower.
 2. The system according to claim 1,wherein the drum support is designed to be mounted to an inner surfaceof a lateral wall or to a support beam of the segment
 3. The systemaccording to claim 2 further comprising at least one releasableconnector for mounting the drum support to an inner surface of a lateralwall or to a support beam of the segment.
 4. The system according toclaim 1, wherein the drum support comprises an axle and an attachmentdevice, wherein the cable drum is rotatably supported to the axle. 5.The system according to claim 4 being configured that the cable drum,axle and attachment device can be disassembled.
 6. The system accordingto claim 4, wherein the axle is fixed to the attachment device and thecable roll is rotatably supported by the axle or the axle is rotatablyheld by the attachment device and the cable roll is fixed to the axle.7. The system according to claim 1 comprising a locking device forpreventing an undesired rotation of the cable drum or a locking devicewhich is configured as a brake.
 8. The system according to claim 1,wherein the cable drum comprises at least one electric cable for a windturbine having a weight of more than 100 kilograms and a length of morethan 60 meters, and the cable drum is designed for carrying andcontrolled releasing of said cable.
 9. The system according to claim 8,wherein the cable drum comprises at least two different types of cableswherein the cables are wound in in a serial and/or parallel manner. 10.A segment for a tower of a wind turbine comprising: a longitudinal axis;a lateral wall surrounding the axis and or a plurality of support beamsarranged partially parallel to the axis; a platform mounted thereinbetween mainly perpendicular to the longitudinal axis for receiving windturbine related personal and equipment; and a system for installing anelectric cable in the tower of a wind turbine comprising at least onecable drum designed for carrying and controlled releasing of at leastone electric cable for a wind turbine and a drum support for rotatablysupporting said at least one cable drum, wherein the drum support ismounted within an interior of the segment.
 11. The segment according toclaim 10, wherein the drum support is mounted to the segment in suchthat the entire cable drum is fully arranged within the interior of thesegment.
 12. The segment according to claim 10 comprising a receptacleon an radially inner surface of the lateral wall or on one of thesupport beams, wherein the receptacle is designed to carry a cablesaddle for supporting electrical cables between a nacelle and the towerduring normal operation of the wind turbine, and the system forinstalling an electrical cable is mounted to the receptacle.
 13. Thesegment according to claim 10 comprising: a longitudinal ladder mountedto the inner surface of the lateral wall or to any of the support beamsof the segment; fixation means for fixing in respect to the segment aplurality of cables to the fixation means, wherein the fixation meansare mounted in such suitable vicinity of the ladder that installationpersonal when present on the ladder is able to access these fixationmeans for mounting the cable thereto.
 14. A method for installing anelectric cable to a tower of a wind turbine, wherein the tower comprisesat least one tower segment having a longitudinal axis, a lateral wallsurrounding the axis and or a plurality of support beams arrangedpartially parallel to the axis, a platform mounted thereinbetween mainlyperpendicular to the longitudinal axis for receiving wind turbinerelated personal and equipment, the method comprising the followingsteps: a. providing a system for installing the electrical cable withinan interior of the at least one tower segment; b. mounting a drumsupport for rotatably supporting at least one cable drum to the interiorof the at least one tower segment; c. mounting at least one cable drumcarrying at least one electric cable for a wind turbine to the drumsupport; d. erecting the tower including lifting the at least one towersegment; e. unwinding the electric cable essentially parallel to thelongitudinal axis through an opening in or near the platform; f. fixingthe cable in respect to the segment; g. optionally repeating steps e) tof).
 15. Method according to claim 14 comprising the step: cutting thecable after step e) or f).
 16. Method according to claim 14, comprisingthe step: disassembling the system into at least two separatecomponents.
 17. Method according to claim 14 comprising the step:disassembling the cable role into at least two separate components. 18.Method according to claim 16 and/or 17 comprising the step: lowering thecomponents down from the platform.
 19. Method according to claim 14comprising the step: mounting a cable saddle for supporting electricalcables between a nacelle and the tower during normal operation of thewind turbine to the inner wall of the segment.
 20. Method according toclaim 14, wherein no electrical power is required and only mechanicalenergy is used.